Electron. J. Differential Equations, Vol. 2025 (2025), No. 109, pp. 1-17.

Evolution psi-Hilfer fractional differential equations in Banach spaces

Jin Liang, Yunyi Mu, Ti-Jun Xiao

Abstract:
This article concerns evolution equations involving \(\psi\)-Hilfer fractional derivative in a Banach space. By using the theory of fractional calculus and \(\psi\)-Laplace transform, we firstly derive a definition of mild solutions for these equations. Then we establish theorems for the existence and uniqueness of solutions and the approximate controllability (not the exact controllability) of the \(\psi\)-Hilfer fractional differential system under appropriate conditions. We focus on the approximate controllability rather than the exact controllability because the exact controllability cannot be achieved generally for the system in infinite-dimensional spaces. We present a new multidimensional Gronwall-type inequality with multiple singular kernels involving exponential factors, which extends essentially many existing results. We also use the new Gronwall-type inequality to study the dependence of the solution on the order and the initial condition for the fractional integro-differential equations involving \(\psi\)-Hilfer fractional derivative. Finally, an example is given to illustrate our main results.

Submitted October 11, 2025. Published November 18, 2025.
Math Subject Classifications: 34K37, 34A08, 45G05, 45E05.
Key Words: psi-Hilfer; mild solution; approximate controllability; Gronwall-type inequality.
DOI: 10.58997/ejde.2025.109

Show me the PDF file (398 KB), TEX file for this article.

Jin Liang
School of Mathematical Sciences
Shanghai Jiao Tong University
Shanghai 200240, China
email: jinliang@sjtu.edu.cn
Yunyi Mu
School of Arts and Sciences
Shanghai Dianji University
Shanghai 201306, China
email: muyy@sdju.edu.cn
Ti-Jun Xiao
Shanghai Key Laboratory for Contemporary Applied Mathematics
School of Mathematical Sciences
Fudan University, Shanghai 200433, China
email: tjxiao@fudan.edu.cn

Return to the EJDE web page